# SDR 2017FA0000552

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: November 4, 2017
- Submitted: November 8, 2017
- Operation: General aviation
- Aircraft: [N417ER](https://openairdocs.org/aircraft/N417ER), registered now
- Make and model: Cessna 172S
- Registry model: [Cessna 172S](https://openairdocs.org/model/cessna-172s) (OpenAirDocs)
- Aircraft serial: 172S11445
- Aircraft time: 3,464 hours
- Engine: Lyc IO360L2A
- Engine time: 3,875 hours
- System (JASC): [8530 · Reciprocating Engine Cylinder Section](https://openairdocs.org/jasc/8530)
- Part: Cylinder Head
- Part number: L1242770
- Condition: Cracked
- Location: Nr 2
- Part time: 1,685 hours
- Stage of operation: CL
- How discovered: O
- Nature of condition: R
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2017FA0000552

## Discrepancy

DURING INITIAL CLIMB, THE CREW EXPERIENCED A SIGNIFICANT POWER LOSS. THE INSTRUCTOR PILOT LANDED THE AIRPLANE ON AN ALTERNATE RUNWAY.  INSPECTION REVEALED A CRACK IN THE NR 2 CYLINDER HEAD ORIGINATING FROM THE INTAKE VALVE SEAT AND CONTINUING THROUGH THE CYLINDER TO THE OUTSIDE BETWEEN THE COOLING FINS. A COMPRESSION CHECK REVEALED A LARGE AMOUNT OF AIR EXITING THROUGH THIS CRACK MAKING AN AUDIBLE HISSING.

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